The proposed project will examine normal embryological development of nonhuman primate preimplantation embryos following exposure to varying freezing regimes. Both in vitro and in vivo fertilized embryos will be used following previous research done in this laboratory to develop those techniques. The assessment of success will initially be the ability of the embryo to resume normal development, after freezing, in vitro and in vivo followed by metabolic studies of the embryo to ascertain normality. In addition, trials will be carried out to develop the necessary techniques for the freezing of unfertilized nonhuman primate ova which can subsequently be fertilized either in vivo or in vitro. In all studies, previously developed and proven techniques for the production of mature nonhuman primate oocytes, their laparoscopic recovery, and their fertilization will be used to maximize data output from the animals without their sacrifice. This work has application not only in studying normal primate embryological development and the effects of freezing, but also for practical assessment of durg induced teratological effects and for the establishment of embryo banks for possible future development of selected animal models for human diseases.